Light-emitting device array with individual cells

ABSTRACT

A light-emitting device and a method for manufacturing the light-emitting device is disclosed. Such a light-emitting device comprises a substrate, a plurality of cells disposed in the substrate, and a plurality of semiconductor dice, wherein each of the plurality of cells accommodates at least one of the plurality of dice. Each of the plurality of cells may be filled with an encapsulant, phosphor or a mixture of an encapsulant with phosphor to control light characteristics of the light-emitting device. In an alternative aspect, cells may be filled with an encapsulant, and comprise a transparent cover coated with or filled with phosphors to control light characteristics of the light-emitting device.

BACKGROUND

1. Field

The present disclosure relates to a light-emitting device, and moreparticularly, to a method and an apparatus for light-emitting devicearrays.

2. Description of Related Technology

A person skilled in the art will appreciate that the concepts disclosedherein are applicable to packages for semiconductor-based light-emittingdevice, namely a light-emitting diode (LED) device.

LEDs have been used for many years in various light requiringapplications, e.g., signaling states for devices, i.e., light on or off,opto-couplers, displays, replacement of bulbs in flashlights, and otherapplications known in the art. Consequently, LEDs emitting both spectralcolors and white light have been developed. There are two primaryapproaches to producing light with desired properties using LEDs. One isto use individual LED dice that emit the three primary colors—red,green, and blue, and then mix the colors to produce light with thedesired properties. The other approach is to use a phosphor material toconvert monochromatic light from a blue or ultra-violet color emittingLED die or dice to a light with the desired properties, much in the sameway a fluorescent light bulb works. For the purposes of this disclosurea die has its common meaning of a light-emitting semiconductor chipcomprising a p-n junction.

Due to LEDs' advantages, i.e., light weight, low energy consumption,good electrical power to light conversion efficiency, and the like, anincreased interest has been recently focused on use of LEDs even forhigh light intensity application, e.g., replacement of conventional,i.e., incandescent and fluorescent light sources, traffic signals,signage, and other high light intensity applications known to a personskilled in the art. It is customary for the technical literature to usethe term “high power LED” to imply high light intensity LED;consequently, such terminology is adopted in this disclosure, unlessnoted otherwise. To increase intensity of the light emitted by thelight-emitting device, often more than one light-emitting die isarranged in a package; such a light-emitting device being termed alight-emitting device array. For the purposes of this disclosure, apackage is a collection of components comprising the light-emittingdevice including but not being limited to: a substrate, a die or dice(if an array), phosphors, encapsulant, bonding material(s), lightcollecting means, and the like. A person skilled in the art willappreciate that some of the components are optional.

A conceptual structure of an exemplary light-emitting device array 100in accordance with known concepts is depicted in FIG. la. Asubstantially flat substrate 102 in addition to being a mechanicalsupport for the electrical and optical layers of the light-emittingdevice is often used as means for heat dissipation from thelight-emitting device array. The electrical and optical layers compriseall the components of the package, excluding the substrate 102. Whenused as means for heat dissipation, the substrate 102 is made from amaterial with high thermal conductivity. Such material may comprisemetals, e.g., Al, Cu, Si-based materials, ceramics such as AN, or anyother material whose thermal conductivity is appropriate for thelight-emitting device array in question. A person skilled in the artwill appreciate that material appropriate for a light-emitting devicearray with power dissipation of, e.g., 35 milliwatts (mW) is differentthan material appropriate for a light-emitting device array with powerdissipation of, e.g., 350 mW. A material is considered to besubstantially flat if the irregularities in flatness would not causelight to be reflected by such irregularities.

The source of light comprises a plurality of dice 114 (three diceshown), disposed on an upper face 104 of the substrate 102. A personskilled in the art will appreciate that the number of dice is a designdecision, and different number of dice can be used to satisfy designgoals.

To improve light extraction from the light-emitting device array 100,several measures are taken. First, surfaces that are transparent tophotons emitted at a particular wavelength or that have poorreflectivity of such photons in an undesirable direction of emission maybe treated, e.g., by polishing, buffing, or any other process, toacquire a specific reflectivity. Reflectivity is characterized by aratio of reflected to incident light. Such surfaces are an upper face104 of the substrate 102 and inner wall 106 of a support member 108. Thesupport member 108 provides boundary for an encapsulant 110 and reflectslight emitted by the dice 114 into desirable direction. Alternatively,the desired reflectivity is achieved by applying a layer of a materialwith high reflectivity, such as Ag, Pt, and any like materials known toa person skilled in the art, (not shown in FIG. 1) onto such surfaces.

Furthermore, to prevent reflection of the emitted photons fromboundaries between materials characterized by different refractionindexes, and, consequently, loss of light intensity, an encapsulant 110is applied into a cavity 112, surrounding the light-emitting region,i.e., the cavity created by the substrate 102, the support member 108,and the dice 114. The material for the encapsulant 110 is selected tomoderate the differences between the refraction indexes of the materialsfrom which components creating the reflective boundaries are made. Inone aspect of the disclosure the encapsulant 110 is transparent;however, the disclosed concepts apply equally to encapsulant 110comprising fillers, e.g., phosphors used for light conversion asdescribed above.

Additionally, light-emitting device array package may further comprise acover 116 disposed above the dice 114. Such a transparent covercomprises e.g., a window or a lens. In order to prevent delamination ofthe encapsulant 110 from the surface of the cover 116 and/or the innerwall of the support member 108 and/or the dice 114 and/or the substrate102, the cover 116 is allowed to float freely on the encapsulant 110,without being rigidly anchored onto the support member 108 with anadhesive or another fastening means. Such a configuration preventssignificant residual stress, caused by temperature variation as thelight-emitting device array 100 heats and cools during the device'slifetime, to develop within the encapsulant 110. Because anydelamination would introduce voids in the encapsulant, the resultinginternal reflection optical losses caused by the above-describeddifference between materials characterized by different refractionindexes would cause loss of light intensity.

Although the configuration depicted in FIG. 1 may be suitable for LEDpackages comprising a clear cover, it is not particularly suitable forLED package comprising a window or lens coated with or filled withphosphors; such a cover being often used for light conversion. Anadvantage of such a configuration is that the window or lens coated withor filled with phosphors can be matched appropriately with a LED dice ofknown wavelength to achieve a more precisely controlled color correctedtemperature (CCT). Different windows or lenses may have differentphosphor coatings or fillings, and these matched with LED dice ofoptimal wavelength to achieve target CCT as needed.

However, a problem with this configuration arises from the fact that thetemperature of the phosphor coated or filled cover increasessignificantly during operation of the light-emitting device arraybecause the conversion inefficiency of the phosphors results ingenerating significant heat. The increase in the temperature in turnresults in decreased efficiency of the light-emitting device array dueto decrease in light-conversion efficiency of the phosphors and decreaseof efficiency of the die.

The above-described problem may be solved by a configuration accordingto FIG. 2, which depicts a conceptual cross section of another exemplarylight-emitting device array 200 in accordance with known concepts. Thedescription of like elements between FIG. 1 and FIG. 2 is not repeated,the like elements have reference numerals differing by 100, i.e.,reference numeral 102 of FIG. 1 becomes reference numeral 202 in FIG. 2.

Referring to FIG. 2, the main conceptual difference from FIG. 1 is thata cover 216 coated with or filled with phosphors is attached to theupper face 218 of the thermally conductive support member 208. Thebottom face 220 of the support member 208 is attached to a thermallyconductive substrate 202. Thus, in this aspect, the support memberfurther serves as supporting means for the cover 216. The cover 216, thesupport member 208, and the substrate 202 should be attached to oneanother using any thermally conductive means (not shown in FIG. 2) tomaximize heat transfer between these components. By the means ofexample, such a thermally conductive means may comprise material such asmetal filled epoxy, eutectic alloy, and any other thermally conductivemeans known to a person skilled in the art. Furthermore, it is desirablethat the cover 216 is also made from a thermally conductive martial.Such a configuration allows heat to flow from the phosphors through thewindow or the lens 216 and then through the support member 208 to thesubstrate 202.

Since additional heat from the cover 216 is now transferred to thesubstrate 202, proper heat dissipation from the LED package 200 must beassured to prevent loss of efficiency due to increased temperature ofthe dice 114. Such heat dissipation may be achieved by proper design ofthe above-described components of the LED package 114. In addition, theLED package 200 may further be attached to a suitable heat sink (notshown).

In any of the above-described configurations, the LED package 200 canoperate without the phosphors or the LED dice over-heating beyondtemperature that would significantly decrease the efficiency of the LEDdice and the phosphors. A person skilled in the art will appreciate thatthe term significant describes a decrease in efficiency that would causethe light-emitting device array performance fail to meet typical orminimum specification over the product life of the light-emitting devicearray.

The above-described structures of a light-emitting device array sufferfrom several shortcomings. The light-emitting device design goaldetermines geometry of the light-emitting device package, which in turndetermines the required quantity of phosphor. Thus, any decrease in thequantity of phosphor would improve economics of production.Additionally, the geometry of the package determines a contact areabetween the phosphor and the substrate, which is subject to a chemicalreaction between the phosphor and substrate, resulting in, e.g.,tarnishing, discoloration, and the like, of the substrate. Thus, anydecrease of the contact area would decrease such undesirable effect,thus improving reliability. Furthermore, the light efficiency is limitedby a light cross-talk, i.e., a condition when a light emitted by one ofthe plurality of dice is absorbed by one or more other dice of theplurality of dice.

Accordingly, there is a need in the art for a light-emitting devicearray providing solution to the above identified problems, as well asadditional advantages evident to a person skilled in the art.

SUMMARY

In one aspect of the disclosure, a light-emitting device array withindividual cells according to appended independent claims is disclosed.Additional aspects are disclosed in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects described herein will become more readily apparentby reference to the following description when taken in conjunction withthe accompanying drawings wherein:

FIG. 1 depicts a conceptual structure of an exemplary light-emittingdevice array in accordance with known concepts;

FIG. 2 depicts a conceptual structure of another exemplarylight-emitting device in accordance with known concepts;

FIG. 3 depicts a conceptual structure of an exemplary light-emittingdevice array in accordance with an aspect of this disclosure;

FIG. 4 depicts a conceptual structure of an exemplary light-emittingdevice array in accordance with another aspect of this disclosure; and

FIG. 5 depicts a conceptual structure of an exemplary light-emittingdevice array in accordance with yet another aspect of this disclosure.

DETAILED DESCRIPTION

Various aspects of the present invention will be described herein withreference to drawings that are schematic illustrations of idealizedconfigurations of the present invention. As such, variations from theshapes of the illustrations as a result, for example, manufacturingtechniques and/or tolerances, are to be expected. Thus, the variousaspects of the present invention presented throughout this disclosureshould not be construed as limited to the particular shapes of elements(e.g., regions, layers, sections, substrates, etc.) illustrated anddescribed herein but are to include deviations in shapes that result,for example, from manufacturing. By way of example, an elementillustrated or described as a rectangle may have rounded or curvedfeatures and/or a gradient concentration at its edges rather than adiscrete change from one element to another. Thus, the elementsillustrated in the drawings are schematic in nature and their shapes arenot intended to illustrate the precise shape of an element and are notintended to limit the scope of the present invention.

It will be understood that when an element such as a region, layer,section, substrate, or the like, is referred to as being “on” anotherelement, it can be directly on the other element or intervening elementsmay also be present. In contrast, when an element is referred to asbeing “directly on” another element, there are no intervening elementspresent. It will be further understood that when an element is referredto as being “formed” on another element, it can be grown, deposited,etched, attached, connected, coupled, or otherwise prepared orfabricated on the other element or an intervening element.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the drawings. It will be understoodthat relative terms are intended to encompass different orientations ofan apparatus in addition to the orientation depicted in the drawings. Byway of example, if an apparatus in the drawings is turned over, elementsdisclosed as being on the “lower” side of other elements would then beoriented on the “upper” side of the other elements. The term “lower” cantherefore encompass both an orientation of “lower” and “upper,”depending of the particular orientation of the apparatus. Similarly, ifan apparatus in the drawing is turned over, elements described as“below” or “beneath” other elements would then be oriented “above” theother elements. The terms “below” or “beneath” can therefore encompassboth an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andthis disclosure.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise,”“comprises,” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. The term “and/or” includesany and all combinations of one or more of the associated listed items.

Various disclosed aspects may be illustrated with reference to one ormore exemplary configurations. As used herein, the term “exemplary”means “serving as an example, instance, or illustration,” and should notnecessarily be construed as preferred or advantageous over otherconfigurations disclosed herein.

Furthermore, various descriptive terms used herein, such as “on” and“transparent,” should be given the broadest meaning possible within thecontext of the present disclosure. For example, when a layer is said tobe “on” another layer, it should be understood that that one layer maybe deposited, etched, attached, or otherwise prepared or fabricateddirectly or indirectly above or below that other layer. In addition,something that is described as being “transparent” should be understoodas having a property allowing no significant obstruction or absorptionof electromagnetic radiation in the particular wavelength (orwavelengths) of interest, unless a particular transmittance is provided.

FIG. 3 depicts a conceptual structure (top and cross-section view) of anexemplary light-emitting device array 300 in accordance with an aspectof this disclosure. A plurality of cells 322 is formed in the substrate302, each of the plurality of cells 322 accommodating at least one ofplurality of dice 314. By proper design of the shape and dimensions ofthe plurality of cells 322, characteristics of the light emitted fromthe plurality of cells 322 can be controlled to eliminate or minimizethe cross-talk among the plurality of dice 314.

A person skilled in the art will appreciate that additional designcriteria may affect the dimensions and shape of each of the plurality ofcells 322. By means of an example, a surface 324 defining a cell 322 maybe shaped as a reflector to improve light extraction by focusing lightemitted by a die 314 into a desired direction. Additionally, oralternatively, the surface 324 defining the cell 322 may be shaped anddimensioned to minimize volume of the cells' 322 cavity in order tominimize an amount of encapsulant, phosphor, and/or encapsulant filledwith phosphor needed to fill the cavity.

Although the surfaces 324 defining the plurality of cells 322 are shownwith an identical shape and dimensions; this is for purposes ofexplanation of the concepts only; in different implementations, thesurfaces 324 may have a different shape and/or dimensions for each ofthe plurality of cells 322.

To improve light extraction from the light-emitting device array 300,the surfaces 324 of the plurality of cells 322 may be treated to acquirea specific reflectivity. In one aspect, such a treatment may comprise,e.g., polishing, buffing, or any other process known to a person skilledin the art.

In an alternative aspect, the desired reflectivity may be achieved byapplying a layer of reflective material on the surfaces 324 of theplurality of cells 322. To maximize luminous efficiency, material withhigh reflectivity, e.g., noble metals like Au, Ag, Pt, or othermaterials like Al, may be used for this purpose. Reflective layersemploying such materials possess predominantly specular reflectivity,unless specific technological process designed to increase diffusivereflectivity is followed.

In yet another aspect, further improvement in luminous efficiency aswell as in spatial light distribution may be obtained by employingreflective surfaces possessing diffusive reflectivity. Consequently, inan alternative, the reflective layer comprises a material with highdiffusive reflectivity.

Although most surfaces poses a mixture of diffuse and specularreflective properties, a person skilled in the art will appreciate thatthe terms specular and diffuse refer to predominant mode of reflection.Thus, as disclosed above, polished or buffed metallic objects and/orlayers of metallic material possess specular reflectivity; mattesurfaces, usually achieved by surface roughness, posses diffusereflectivity.

Furthermore, the upper surface 326 of the substrate 302 between theplurality of cells 322 may be treated in an identical or a similarmanner in accordance with design criteria. Thus, by means of an example,the surfaces 324 of the plurality of cells 322 may be treated bypolishing and/or buffing, while diffusive reflective layer may beapplied on the upper surface 326 of the substrate 302.

The isolation between the plurality of cells 322 allows further controlof characteristics of the light emitted by the light-emitting device 300by enabling control of characteristics of light emitted from eachindividual cell 322 by an appropriate selection of a die 314, anencapsulant, phosphor and/or an encapsulant filled with phosphordisposed into the cavity of each individual cell 322. The combination ofdice, encapsulant, phosphor and/or an encapsulant filled with phosphorfor each cell in the light-emitting device 300 is a criterion criteriabased on design goals. Thus, by means of an example, FIG. 3 depicts twocorner cells 322, e.g., the cross-hatched cells, filled with phosphor oran encapsulant filled with phosphor of first color; two corner cells322, e.g., the honeycomb-hatched cells, filled with phosphor or anencapsulant filled with phosphor of second color, and four cells filledwith an encapsulant.

The light-emitting device array 300 may further comprise a cleartransparent cover 316 used for protection of the light-emitting devicearray 300 from environmental conditions. The term “clear” used hereinmeans a transparent cover without any coat or fill of phosphor(s). Sucha clear transparent cover 316 comprises e.g., a window or a lens.

Alternatively, to further control characteristics of the light, thecover 316 may be coated with or filled with phosphors.

The specific configuration and placement of the transparent cover 316 isa criterion based on design goals. By means of an exemplaryconfiguration, the transparent cover 316 may be disposed directly on, asshown in FIG. 3, or above the upper surface 326 of the substrate 302.

FIG. 3 a depicts a cross-section view of an alternative aspect ofcontrolling characteristics of the light emitted by the light-emittingdevice 300 by controlling characteristics of the light emitted from eachindividual cell 322. As depicted in FIG. 3 a, the transparent covercomprises a plurality of transparent covers 316, each of the pluralityof transparent covers 316 being disposed over one the plurality of cells322 and being coated or filled with phosphor. Thus, the characteristicsof light emitted from each individual cell 322 is controlled by anappropriate selection of the die 314 disposed in each cell 322 andphosphor used to coat or fill the transparent cover 316 disposed overeach cell 322. To prevent reflection of emitted photons from boundariesbetween materials characterized by different refraction indexesencapsulant may be applied into the cells' 322 cavities.

An additional clear transparent cover 328 may be disposed on or above,as shown in FIG. 3 a, the plurality of transparent covers 316 to protectthe light-emitting device array 300 from environmental conditions.Alternatively, to further control characteristics of the light the cover328 may be coated with or filled with phosphors. To prevent reflectionof emitted photons from boundaries between materials characterized bydifferent refraction indexes encapsulant may be applied into the cavitydelimited by the substrate 302, the plurality of covers 316, and thecover 328.

A person skilled in the art will understand that the aspects disclosedin FIG. 3 and FIG. 3 a regarding controlling characteristics of thelight emitted from each individual cell may be combined in accordancewith design goals for the light-emitting device array. Consequently, thecharacteristics of light emitted from each individual cell 322 may becontrolled by an appropriate selection of the die 314 disposed in eachcell 322; the filling material disposed into the cavity of eachindividual cell 322; and the transparent cover(s) 316 and/or 328. Theselection of die 314 comprises selection of die with appropriate lightcharacteristics; the filling material may comprise no filling material,an encapsulant, phosphor, and/or an encapsulant filled with phosphor;and the transparent cover(s) 316 and/or 328 comprise any combination ofclear and phosphor coated or filled cover, configured as a window or alens.

FIG. 4 depicts a conceptual structure (top and cross-section view) of anexemplary light-emitting device array package 400 in accordance withanother aspect of this disclosure. A plurality of cells 422 is formed onthe substrate 402, each of the plurality of cells 422 accommodating atleast one of plurality of dice 414. The plurality of cells 422 iscomprised of a plurality of support members 408. By proper design of thedimensions and shape of each of the plurality of support members 408,the characteristics of the light emitted from the plurality of cells 422can be controlled to eliminate or minimize the cross-talk among theplurality of dice 414.

A person skilled in the art will appreciate that additional designcriteria may affect the dimensions and shape of each of the plurality ofsupport members 408. Thus, by means of an example, in the cross-sectiondrawings of FIG. 4-FIG. 4 b, a surface 424 of the support member 408,defining a cell 422 is cylindrical-shaped. However, other exemplaryshapes, e.g., as described in reference to FIG. 3 are within the scopeof this aspect. Although the surfaces 424 defining the plurality ofcells 422 are shown with an identical shape and dimensions; this is forpurposes of explanation of the concepts only; in differentimplementations, the surfaces 424 may have a different shape and/ordimensions for each of the plurality of cells 422.

To improve light extraction from the light-emitting device array 400,the surfaces 424 of the plurality of cells 422 may be treated to acquirea specific reflectivity. In one aspect, such a treatment may comprise,e.g., polishing, buffing, or any other process known to a person skilledin the art.

In an alternative aspect, the desired reflectivity may be achieved byapplying a layer of reflective material on the surfaces 424 of theplurality of cells 422. To maximize luminous efficiency, material withhigh reflectivity, e.g., noble metals like Au, Ag, Pt, or othermaterials like Al, may be used for this purpose. Reflective layersemploying such materials possess predominantly specular reflectivity,unless specific technological process designed to increase diffusivereflectivity is followed.

In yet another aspect, further improvement in luminous efficiency aswell as in spatial light distribution may be obtained by employingreflective surfaces possessing diffusive reflectivity. Consequently, inan alternative, the reflective layer comprises a material with highdiffusive reflectivity applied.

Although most surfaces poses a mixture of diffuse and specularreflective properties, a person skilled in the art will appreciate thatthe terms specular and diffuse refer to predominant mode of reflection.Thus, as disclosed above, polished or buffed metallic objects and/orlayers of metallic material possess specular reflectivity; mattesurfaces, usually achieved by surface roughness, possess diffusereflectivity.

Furthermore, the upper surface 426 of the substrate 402 between theplurality of cells 422 may be treated in an identical or similar mannerin accordance with design criteria. Thus, by means of an example, thesurfaces 324 of the plurality of cells 322 may be treated by polishingand/or buffing, while diffusive reflective layer may be applied on theupper surface 326 of the substrate 302.

The light-emitting device array 400 further comprises a transparentcover 428. As depicted in FIG. 4, the transparent cover 428 is disposeddirectly on the upper face of the support members 408, thus delimiting,together with the substrate 402 and the plurality of support members408, the cells' 422 cavity. The physical isolation between the pluralityof cells 422 allows further control of characteristics of the lightemitted by the light-emitting device 400 by enabling control ofcharacteristics of light emitted from each individual cell 422 by anappropriate selection of a die 414, an encapsulant, phosphor and/or anencapsulant filled with phosphor disposed into the cavity of eachindividual cell 422. The combination of dice, encapsulant, phosphorand/or an encapsulant filled with phosphor for each cell in thelight-emitting device 400 is a criterion based on design goals. Thus, bymeans of an example, FIG. 4 depicts two corner cells 422 filled withphosphor or an encapsulant filled with phosphor of first color, e.g.,the cross-hatched cells; two cells filled with phosphor or anencapsulant filled with phosphor of second color, e.g., thehoneycomb-hatched cells, and four cells filled with an encapsulant.

The transparent cover 428 may be clear if the cover's primary purpose isan environmental protection; alternatively, to further controlcharacteristics of the light the cover 416 may be coated with or filledwith phosphors.

FIG. 4 a depicts a cross-section view of an alternative aspect ofcontrolling characteristics of the light emitted by the light-emittingdevice 400 by controlling characteristics of the light emitted from eachindividual cell 422 Like in FIG. 4, the plurality of cells 422 iscomprised of a plurality of support members 408. In contrast from FIG.4, the transparent cover comprises a plurality of transparent covers 416in a form of a window, each of the plurality of transparent covers 416being disposed over one the plurality of cells 422 and being coated orfilled with phosphor.

Thus, the characteristics of light emitted from each individual cell 422is controlled by an appropriate selection of the die 414 disposed ineach cell 422 and phosphor used to coat or fill the transparent cover416 disposed over each cell 422. To prevent reflection of emittedphotons from boundaries between materials characterized by differentrefraction indexes, the cells' 422, cavity delimited by the substrate402, the support member 408, and the plurality of covers 416 may befilled with encapsulant.

An additional clear transparent cover 428 may be disposed on or above,as shown in FIG. 4 a, the plurality of transparent covers 416 to protectthe light-emitting device array 400 from environmental conditions.Alternatively, to further control characteristics of the light the cover428 may be coated with or filled with phosphors. To prevent reflectionof emitted photons from boundaries between materials characterized bydifferent refraction indexes encapsulant may be applied into the cavitydelimited by the substrate 402, the plurality of covers 416, and thecover 428.

FIG. 4 b depicts a cross-section view of yet an alternative aspect ofcontrolling characteristics of the light emitted by the light-emittingdevice 400 by controlling characteristics of the light emitted from eachindividual cell 422. The difference from FIG. 4 a, is that each of theplurality of transparent covers 416 comprise a lens to focus lightemitted each of the cell's 422 into an appropriate direction.

A person skilled in the art will understand that the aspects disclosedin FIG. 4-FIG. 4 b regarding controlling characteristics of the lightemitted from each individual cell may be combined in accordance withdesign goals for the light-emitting device array. Consequently, thecharacteristics of light emitted from each individual cell 422 may becontrolled by an appropriate selection of the die 414 disposed in eachcell 422; the filling material disposed into the cavity of eachindividual cell 422; and the transparent cover(s) 416 and/or 428. Theselection of die 414 comprises selection of die with appropriate lightcharacteristics; the filling material may comprise no filling material,an encapsulant, phosphor, and/or an encapsulant filled with phosphor;and the transparent cover(s) 316 and/or 328 comprise any combination ofclear and phosphor coated or filled, window or a lens.

A person skilled in the art will appreciate, that the plurality of cellsmay be constructed by many different technologies. In addition to theexemplary constructions disclosed in FIG. 3 and FIG. 4, the plurality ofcells 522 may be constructed by dispensed material as a grid definingsupport members 508 on the substrate 502, using any of the dispensingtechniques known to a person skilled in the art, as depicted in FIG. 5.Because FIG. 5 differs from FIG. 3 and/or FIG. 4 mainly by thetechnology of construction of the plurality of cells, all the conceptsregarding control of characteristics of the light emitted by thelight-emitting device by enabling control of characteristics of lightemitted from each individual cell apply equally.

The various aspects of this disclosure are provided to enable one ofordinary skill in the art to practice the present invention.Modifications to various aspects of a presented throughout thisdisclosure will be readily apparent to those skilled in the art, and theconcepts disclosed herein may be extended to other applications. Thus,the claims are not intended to be limited to the various aspects of thereflective surfaces for a light-emitting device array presentedthroughout this disclosure, but are to be accorded the full scopeconsistent with the language of the claims. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. §112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or, in the case of a method claim, theelement is recited using the phrase “step for.”

1. A light-emitting device, comprising: a substrate; a plurality ofcells disposed in the substrate; and a plurality of semiconductor dice;wherein each of the plurality of cells accommodates at least one of theplurality of dice.
 2. The apparatus according to claim 1, wherein anencapsulant is disposed into each of the plurality of cells.
 3. Theapparatus according to claim 1, wherein phosphor is disposed into atleast one of the plurality of cells.
 4. The apparatus according to claim1, wherein an encapsulant filled with phosphor is disposed into at leastone of the plurality of cells.
 5. The apparatus according to claim 4,wherein an encapsulant is disposed into each of the plurality of cellsnot containing the encapsulant filled with phosphor.
 6. The apparatusaccording to claim 4, wherein at least two of the plurality of cellscontain the encapsuland filled with phosphor of different color.
 7. Theapparatus according to claim 1 further comprising a plurality oftransparent covers, each of the plurality of covers being disposed overone of the plurality of cells.
 8. The apparatus according to claim 7,further comprising an encapsulant disposed into each of the plurality ofcells.
 9. The apparatus according to claim 7, wherein at least one ofthe plurality of the transparent covers is coated with or filled withphosphor.
 10. The apparatus according to claim 7, wherein at least twoof the plurality of the transparent covers are coated with or filledwith phosphor of different color.
 11. A method for manufacturing alight-emitting device, comprising: manufacturing a substrate; disposinga plurality of cells in the substrate; and disposing a plurality of diceinto the plurality of cells; wherein each of the plurality of cellsaccommodates at least one of the plurality of dice.
 12. The methodaccording to claim 11, further comprising disposing an encapsulant intoeach of the plurality of cells.
 13. The method according to claim 11,further comprising disposing phosphor into at least one of the pluralityof cells.
 14. The method according to claim 11, further comprisingdisposing an encapsulant filled with phosphor into at least one of theplurality of cells.
 15. The method according to claim 14, wherein anencapsulant is disposed into each of the plurality of cells notcontaining the encapsulant filled with phosphor.
 16. The methodaccording to claim 14, wherein at least two of the plurality of cellscontains the encapsuland filled with phosphor of different color. 17.The method according to claim 11 further comprising disposing atransparent cover over each of the plurality of cells.
 18. The methodaccording to claim 17, further comprising disposing an encapsulant intoeach of the plurality of cells.
 19. The method according to claim 17,wherein at least one of the plurality of the transparent covers iscoated with or filled with phosphor.
 20. The method according to claim17, wherein at least two of the plurality of the transparent covers arecoated with or filled with phosphor of different color.